Sealing composition



I Nov. 6, 1945. N, P NN N 2,388,568

SEALING COMPOSITION Filed March 4, 1942 Patented Nov. 6, 1945 UNITEDSTATES PATENT OFFICE.

QOM QSITIQN Nicholas J Penning, Milwaukee, Wis. Application March 4,1942, Serial No, 433,367

11 Claims,

Crown bottle caps, those caps which are ap-- plied to beer and softdrink bottles, require a sealing member compressed between them and therim of the bottle in order to effectuate a seal. These sealing membersor seals, u as they are commonly called have conventionally been formedof a thin disc of cork or cork composition faced on the side exposed tothe bottle contents with a disc of tin foil or the like, called a spot.

These seals have never been completely satisfactory because of atendency for the formation 01f mold beneath the spot. They have,however, been more satisfactory than anything else com merciailyavailable, At the present time, in fact, even, these seals can hardly besaid to be commercially available in view of the material shortage,especiallyin tin foil.

One reason that mother seal has been as satisfactory is because of; thedifiieulty of avoiding the impartation of taste or odor to the contentsoi the bottle, Even tastes or smells which most people would not noticewould be noticed by enough, people so that the reputation of a productparticularly in; the case of a beverage, would'be impaired. Anotherfactor that must be taken into consideration is the pressure with whichthe caps are conventionally applied. A material which is too soft willflow under this pressure with the result that, when-the pressure isreleased, there may be leakage. On the other hand, it is necessary forthe material t be yieldable in order to efiectuate a satisfactory seal.Another requirement is that the material should not be tacky-it shouldnot adhere to the glass.

According to the present invention, the various requirements have beenmet by the. use of a ubbar and wood flour compositionsubstantially ireefrom any ingredients which will import taste or odor to the contents ofthe bottle and which can be manufactured at a sumoiontly low cost to becommercially practical! Of course, he price must be low enough to bepractically insls ifioant in relation o t to al ost of t bottled be rae,- The proper c nsistency is obtainedwithout th oo toi ul anization byheat by using a elativel high content of filler h ch is largely woodflour and by mixing he u be and fi ler i such a way as o av a largeproportion of the natural rubber globules unbroken.

Additional advantages and objects of the invention will be apparent fromthe following description and from the-drawings, which showin crosssection and more or less diagrammatically a bottle cap applied to abottle and embody ng the seal oi the nro eu inven n,

althou h only one term, oi bottle tap and seal have been illustrated.tho io m of cap being tha for which the present n ent on s pa ticular ydesigned, it will. be evident that o e for of cars can be sed and that wde d pa tures may be made from tho oroi rred, oomp sition of th s alwhile retainin at least s me of the advanta es oi the presentinvention-,

F1111 details of the p eferred co position and its treatment given. n ao rdance wi h h requ ements oi R, @88 but are not intend for lim tationof; th sco e o the. invention e e cent as requir by the prior art.

in the drawing the. bottle oar? H. app ied o a b tle. .2 a conventionalmann r and ineludes a conventional or mp d fl e which exerts a pressureon the uh orsid of an, annular bead 4 at th mou h of the bottle to holdt e can firm y bi ta Ho motio seal ng f, h bottle s ofi otuatocl. by aseal 6 with wh ch t present invention is par u ar y c no h dit may beinserte loose or cemented with adhesives lior toi e used in bottl aps,as a bumen for example,

As seen iron; he drawing. e sea 6 may coinrise a single; layer,v As prvi sly mentioned, it is necessary for the seal. to be yieldable toeffectuate the seal and. as a mat er oi act, it is a so necssary for itto be resilient so that alter the pressure used in applying the canreleased the seal will tend to expand and continue t ex rt a pressureagainst the bottle, arious ru ber ompsitions have been trie the past bute l been f u d to be unsot s a tor-y, e ther becaus they lacked the riht consistency or because they imparted taste to the contents of he botle,

ccord to the present inventi n. the preferred composition and method offormation of the seal l6 are as follows, the proportions. being byweight throughout:

Leaohed maple wood flour Pale crepe rubber fl ur-ore mixed y first applying the rubber to a standard ru ber mi l having its rolls heated toaoprozdmately 0 .1. and l Flying the wood flour thereto as soon as therubber begins to level out, which will usually be in about one minute.The mixture should be removed from the mill as soon as the wood flourhas been well incorporated and uniformly mixed through the rubber, whichwill usually be within four minutes more. After cooling, the mixture isthen calendered, the rolls of the calender being warm, according toconventional practice, a temperature of 150 F. bei ng satisfactory.

It will be evident that wide departures can be made from the foregoingformula and treatment. Some departures will have no deleterious efiect.Others will cause a failure to obtain the full advantages of theinvention but will still yield asatisfactory sealing composition. Forexample, considerable departure may be made from the milling temperaturestated, but best results are obtained by having the temperatureapproximately as high as 300 F., since this permits a rapid mixing ofthe rubber and wood flour Without greatly breaking down the rubber. Inother words, a substantial proportion of the rubber globules areretained unbroken in their original state. For those not skilled in theart,- it may be noted that rubber latex is formed of very minute rubberglobules in an aqueous suspension, some resins and proteins beingpresent in addition to the rubber molecules and water. In the course offorming pale crepe from this latex, most of the water is removed and aconsiderable proportion of the-other non-rubber ingredients are washedout, and it is probable that some of the rubber globules are broken. Thebrief mixing on the hot mill preferred, by maintaining as many aspossible of the globules intact, results in a finished product which hasthe proper consistency without vulcanization. 1.

In place of wood flour, any other ground fibrous cellulose may beusedfor example, ground corncobs or corn stalk 'pith. For many uses,however, as for example with beer, care must be taken to choose onewhich will not impart a taste to the contents of the bottle. Ihave'determined that, considering availability, the very best from awide variety of possibilities is rock maple ground to a flour, and thatit is improved by the leaching process mentioned. Quite a few othersmight be found that would be satisfactoryfor anyigiven purpose,especially if leached to remove taste-imparting or'taste destroyingingredients. Of course, non-cellulosic fibrous materials could alsobe'used if they meet the other tests. They should, however, be in verysmall particles comparable to .the particle size of wood flour, ratherthan in lon fibers. It is believed to be desirable for the smallparticles to themselves be composed of a plurality of extremely finefibres so that they will tend to interlock with one another and preventflowing of the finished product under the pressure of capping thebottle. 7 H

It is not necessary that all of the filler be of this fibrous nature.Fairly satisfactory resultshave been obtained with only of the totalWeight composed of wood flour, the remainder of the filler being amineral such as clay. The seal should not be tacky enough to sticktoglass and hence total filler content should be about 60% to about 80%of the total weightif all wood flour, or the equivalent thereofinreducing tackiness. r

Although pale'crepe rubber i's'preferred, any other rubber or similarrubber-like substance, in-' cluding synthetic rubber, which will notimpart a taste or smell, and which will yieldthei proper consistency ofthe finished product may'beused. The consistency should'be similar tothat of pork,

. impervious to moisture.

are,cut to a half-hour curing with the'vapor of' a small amount ofsulphur chloride in a closed container at room temperatures, atemperature of about 70 F. having been specifically found to besuitable.

A suitable substance may be included if desired for rendering theindividual wood flour particles One suitable substance is that known asFlex Wax C sold by Glyco Products Company of New York city. It isnontoxic and insoluble in alcohol and in water and melts to a liquid atabout F. and does not affect the taste or smell of beverages in contacttherewith. The wax may further be identified as that specific waxdisclosed in the publication "Chemicals by Glyco, copyright 1940,especially at page 34. Properties of this Wax include the following:Color-tan, luster-dull, flash point- 257 C., specific gravity at 20C.-.820, soluble in hot tallow oil, hot naphtha, hot mineral oil,

and hot vegetable oil, the solution in vegetable oil gelling when cold.It is mixed simultaneously with the wood flour and rubber and issubstantially sorbed (probably absorbed) bythe flour.

Five per cent of the weight of the mixture to' which it is added ispreferred, but from 3 to 20% may be used advantageously. Being sorbed,it has little efiect on' the proportions that should be used aside fromthe wax.

A seal produced in accordance with the foregoing disclosure, evenwithout the treatment with. sulphur chloride, produces a moresatisfactory, seal than any known befor this invention. It is.

adequately impervious to liquids and gas; it is immune to alcoholic andaqueous solutions; it imparts no detectable taste or odor to suchsolutions or beverages; and it has the proper consistency includingresistance to flow and resiliency. Furthermore, it can be made at a verylow cost because of the fact that its major ingredient, wood flour, isvery inexpensive and the further fact that it requires no vulcanizationand hence may be made simply by brief mixing and calendering. In theformin which the composition is surface-vulcanized with; sulphurchloride, it can be used in contactwith hydrocarbon solvents. For thispurpose it will not ordinarily need to be free from taste or odorimparting ingredients. When..vlucanized throughout with sulphurchloride, it is suitable for numerous other uses where it may besubjected to pressures considerably greater than the conventionalbottling pressures.

'Iclaim: I l w r 1. A bottle-sealing composition consisting essentiallyof 25 parts by weight of pale crepe rubber, and approximately 75 partsof rockmaple wood flour thoroughly mixed therein; said rubber beingsubstantially unbroken-down, and said compound having such a consistencythat it will yield resiliently but will not appreciably flow underconventional bottle-sealing practices.)

,2. A bottle cap comprising a, disc of. metal having a crimped flangetherearound anda preformed sealing member inserted therein formed of thecomposition set forth in claim 1.

3. The method of making bottle seals, which consists essentially inboiling rock maple wood flour in water, decanting the water, applyingpale crepe rubber to a hot mill, adding the wood flour to the rubber assoon as the rubber begins to level out until the wood flour is about 75%of the total by weight, removing the mix as soon as the wood flour hasbeen well incorporated, calendering the mix, and cutting the seals fromthe resulting sheet.

4. A composition consisting essentially of unvulcanized rubber, and afiller consisting mainly of maple wood flour, with the filler comprising60-80% of the weight.

5. A sealing composition consisting essentially of unvulcanized rubbermatrix and a filler in a proportion equivalent in eliminating tackinessto 60% by weight of wood flour, a portion of the filler, comprising atleast 33% of the matrix weight, comprising maple wood flour.

6. A sealing composition consisting essentially of unvulcanized rubbermatrix and a filler in a proportion suflicient to prevent the rubberfrom sticking to glass, a portion of the filler, comprising at least 33%oi. the matrix weight, comprising maple wood flour.

7. A bottle sealing disk having the composition set forth in claim 6.

8. A bottle-sealing composition consisting essentially of 25 parts byweight of pale crepe rubber, and approximately to parts of maple woodflour thoroughly mixed therein, the said rubber being substantiallyunbroken-down; and said compound having such a consistency that it willyield resiliently but will not appreciably flow under conventionalbottle-sealing practices.

9. A bottle-sealing disc formed of the composition set forth in claim 8.

10. A bottle-sealing composition consisting es- 7 sentially of palecrepe rubber and at least twice the weight thereof of maple wood flourthoroughly mixed therein; the said rubber being substantiallyunbroken-down, and said, compound having such a consistency that it willyield resiliently but will not appreciably flow under conventionalbottle-sealing practices.

11. A bottle-sealing disc formed of the composition'set forth in claim10.

* NICHOLAS J. PENNJNG.

